In charging for printing, charges are sometimes different for two kinds of printing, i.e., color printing and monochrome printing. In this case, the charge for the color printing is higher than the charge for the monochrome printing because of toners and the like used in the printing.
If only a part of colors are included in an original document to be printed, a charge increases when charging for an entire page or an entire job is treated as charging in the color printing. Therefore, if only slight colors are included in one page, low color charging in which a charge between normal charges for the color printing and the monochrome printing is set is provided as a charge structure. In the low color charging, a pixel counter that calculates outputs of toners or inks of respective colors in an image forming apparatus indicates consumption equal to or smaller than a specified amount in one page, the low color charging is applied.
However, in this method, there is a problem in that a user does not see whether the color charging or the low color charging is applied.